Image pickup element, image pickup apparatus, and method of manufacturing image pickup element

ABSTRACT

Image quality is improved. 
     In an image pickup element, an interval between adjacent light receiving elements on a light receiving surface is changed depending on a position on the light receiving surface. Further, the image pickup element is manufactured by a method of manufacturing the image pickup element including layering photodiodes by repeatedly performing a silicon epitaxial process and an ion injection process. Further, the image pickup element is manufactured by the method of manufacturing the image pickup element including changing an interval between the photodiodes adjacent on the light receiving surface of the image pickup element in each layer depending on a position on the light receiving surface in addition to the layering thereof.

TECHNICAL FIELD

The present technology relates to an image pickup element. Specifically,the present technology relates to an image pickup element that generatesimage data, an image pickup apparatus, and a method of manufacturing animage pickup element.

BACKGROUND ART

In related art, an image pickup element that takes an image of a subjectand generates image data thereof exists. For example, image pickupelements such as a CMOS (Complementary Metal Oxide Semiconductor) and aCCD (Charge Coupled Device) are in widespread use.

Further, for example, there has been proposed such an image pickupelement that positions where sensor separation layers are formed are setto be different depending on travelling directions of light that entersa substrate between a pixel area center portion and a pixel areaperipheral portion (see, for example, Patent Literature 1).

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Application Laid-open No.2010-118479

DISCLOSURE OF INVENTION Technical Problem

In related art described above, by setting the positions where thesensor separation layers to be different, color mixing can besuppressed.

Further, for example, it is important to suppress color mixing andshading by pupil correction or the like, and improve the image qualityof image data generated by an image pickup element.

The present technology has been made in view of the circumstances asdescribed above and has an object to improve image quality.

SOLUTION TO PROBLEM

According to a first aspect of the present technology, there is providedan image pickup element, in which an interval between adjacent lightreceiving elements on a light receiving surface is changed depending ona position on the light receiving surface. With this structure, aneffect of generating image data by the image pickup element in which theinterval between the adjacent light receiving elements on the lightreceiving surface is changed depending on the position on the lightreceiving surface is obtained.

Further, according to the first aspect, the image pickup element may bea back-surface irradiation type COMS (Complementary Metal OxideSemiconductor) sensor, in which the light receiving elements may beformed in such a manner that the adjacent light receiving elements arearranged at an equal interval on a pixel transistor side, and the lightreceiving elements may be formed in such a manner that the adjacentlight receiving elements are arranged at different intervals dependingon positions on the light receiving surface on a light incident side.With this structure, obtained is an effect of generating image data bythe back-surface irradiation type CMOS sensor in which on the pixeltransistor side, the light receiving element is formed in such a mannerthat the interval between the adjacent light receiving elements isequal, and on the light incident side, the light receiving element isformed in such a manner that the adjacent light receiving elements arearranged at different intervals depending on the position on the lightreceiving surface.

Further, according to the first aspect, the light receiving elements maybe formed along light paths of light incident from opening portions ofthe light receiving elements. With this structure, obtained is an effectof generating image data by the image pickup element in which the lightreceiving elements are formed along the light path of light incidentfrom opening portions of the light receiving elements.

Further, according to the first aspect, the light receiving elements maybe divided into pieces and silicon-epitaxially formed. As a result,obtained is an effect that image data is generated by the image pickupelement in which the light receiving elements are divided into piecesand formed by the silicon epitaxial process.

Further, according to the first aspect, the intervals between theadjacent light receiving elements may be linearly or nonlinearly changedfrom a center of the light receiving surface toward field angle ends.With this structure, obtained is an effect of generating image data bythe image pickup element in which the intervals between the adjacentlight receiving elements are linearly or nonlinearly changed from thecenter of the light receiving surface toward field angle ends.

Further, according to the first aspect, an interval between inter-pixellight shielding films disposed between the adjacent light receivingelements may be changed depending on a position on the light receivingsurface. With this structure, obtained is an effect of generating imagedata by the image pickup element in which the interval betweeninter-pixel light shielding films disposed between the adjacent lightreceiving elements is changed depending on the position on the lightreceiving surface.

Further, according to the first aspect, an interval between lensesdisposed on the light receiving elements may be changed depending on aposition on the light receiving surface. With this structure, obtainedis an effect of generating image data by the image pickup element inwhich the interval between the lenses disposed on the light receivingelements is changed depending on the position on the light receivingsurface.

Further, according to a second aspect of the present technology, thereis provided a method of manufacturing an image pickup element,including: layering photodiodes by repeatedly performing a siliconepitaxial process and an ion injection process; and changing an intervalbetween the photodiodes adjacent on a light receiving surface of animage pickup element in each layer depending on a position on the lightreceiving surface. As a result, obtained is an effect of layering thephotodiodes by repeatedly performing the silicon epitaxial process andthe ion injection process and changing the interval between thephotodiodes adjacent on the light receiving surface of the image pickupelement in each layer depending on the position on the light receivingsurface.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present technology, it is possible to exert theexcellent effect that the image quality can be improved. It should benoted that, the effects described here are not limited, and any effectdescribed in this disclosure may be obtained.

BRIEF DESCRIPTION OF DRAWINGS

[FIG. 1] A cross-sectional view showing a configuration example of animage pickup element 100 according to a first embodiment of the presenttechnology.

[FIG. 2] Top plan views each showing a configuration example of theimage pickup element 100 according to the first embodiment of thepresent technology.

[FIG. 3] A diagram showing an example of a manufacturing process of theimage pickup element 100 according to the first embodiment of thepresent technology.

[FIG. 4] A diagram showing an example of a manufacturing process of theimage pickup element 100 according to the first embodiment of thepresent technology.

[FIG. 5] A diagram showing an example of a manufacturing process of theimage pickup element 100 according to the first embodiment of thepresent technology.

[FIG. 6] A diagram showing an example of a manufacturing process of theimage pickup element 100 according to the first embodiment of thepresent technology.

[FIG. 7] A diagram showing an example of a manufacturing process of theimage pickup element 100 according to the first embodiment of thepresent technology.

[FIG. 8] A diagram showing an example of a manufacturing process of theimage pickup element 100 according to the first embodiment of thepresent technology.

[FIG. 9] A diagram showing an example of a manufacturing process of theimage pickup element 100 according to the first embodiment of thepresent technology.

[FIG. 10] A diagram showing an example of a manufacturing process of theimage pickup element 100 according to the first embodiment of thepresent technology.

[FIG. 11] A cross-sectional view showing a configuration example of animage pickup element 200 according to a second embodiment of the presenttechnology.

[FIG. 12] A diagram showing an example of a manufacturing process of theimage pickup element 200 according to the second embodiment of thepresent technology.

[FIG. 13] A diagram showing an example of a manufacturing process of theimage pickup element 200 according to the second embodiment of thepresent technology.

[Fig. 14] A cross-sectional view showing a configuration example of animage pickup element 300 according to a third embodiment of the presenttechnology.

[FIG. 15] A cross-sectional view showing a configuration example of animage pickup element 400 according to the third embodiment of thepresent technology.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, modes for carrying out the present technology (hereinafter,referred to as embodiments) will be described. The description will begiven in the following order.

1. First embodiment (example of image pickup element such asback-surface irradiation type CMOS sensor)2. Second embodiment (example of image pickup element such asfront-surface irradiation type CMOS sensor)3. Third embodiment (example of image pickup element of multilayersilicon epitaxial of three or more layers)

1. First Embodiment [Configuration Example of Image Pickup Element]

FIG. 1 is a cross-sectional view showing a configuration example of animage pickup element 100 according to a first embodiment of the presenttechnology. FIG. 1 shows the configuration example of a peripheralportion of the image pickup element 100 (area on a peripheral side on alight reception surface).

The image pickup element 100 is provided with OCLs (On Chip Lenses) 111to 114, OCCFs (On Chip Color Filters) 121 to 124, inter-pixel lightshielding films 131 to 134, photodiodes 141 to 146, and pixeltransistors 151 to 153. The image pickup element 100 is achieved by aback-surface irradiation type COMS (Complementary Metal OxideSemiconductor) sensor, for example.

The OCLs 111 to 114 are micro lenses disposed above pixels, and collectlight from a subject to the photodiodes 141 to 146.

The OCCFs 121 to 124 are color filters disposed above the pixels, andthe pixels obtain color information corresponding to the OCCFs disposedthereabove.

The inter-pixel light shielding films 131 to 134 are light shieldingfilms formed along a boundary between adjacent pixels. The inter-pixellight shielding films 131 to 134 are made of a material that shieldslight.

The photodiodes 141 to 146 are light receiving elements that receivelight collected by the OCLs 111 to 114.

The pixel transistors 151 to 153 are reading transistors used when pixeldata accumulated by receiving light by the photodiodes 141 to 146 isread.

FIG. 2 shows top plan views each showing a configuration example of theimage pickup element 100 according to the first embodiment of thepresent technology.

In a of FIG. 2, a pixel area 160 in the case of viewing the image pickupelement 100 from above is simply shown. It should be noted that, in a ofFIG. 2, for ease of explanation, the pixel area 160 of the image pickupelement 100 is shown as a substantially square rectangle.

In b of FIG. 2, a relationship between photodiode opening portions andthe OCLs in the case of viewing the image pickup element 100 from above.It should be noted that, in b of FIG. 2, for ease of explanation, thenumber of pixels that constitute the image pickup element 100 is set toonly 25, and the pixels are schematically shown by rectangles. Further,the photodiode opening portions in the pixels are shown by substantiallyrectangles (shapes obtained by rounding off four corners of therectangles), and the OCLs are shown by circles. For example, in a pixel170, a photodiode opening portion 171 and an OCL 172 are disposed.

As shown in b of FIG. 2, from the center of a pixel area toward fieldangle ends thereof, the areas of the photodiode opening portions 171 areshifted linearly (or nonlinearly) in the pixels 170. For example, asshown in a of FIG. 2, from a center 161 of the pixel area 160 indirections indicated by arrows 162 and 163, the areas of the photodiodeopening portions 171 are shifted linearly. For example, shift amounts ofthe areas of the photodiode opening portions 171 can be increased (forexample, increase based on a predetermined rule (for example, monotoneincrease)) as shifted from the center 161 to the arrows 162 and 163directions.

Further, for example, as shifted from the center 161 of the pixel area160 to the arrows 162 and 163 directions, at least a part of the areasof the photodiode opening portions 171 may be nonlinearly shifted. Forexample, the shift amount of the part of the areas of the photodiodeopening portions 171 is increased (for example, increase based on apredetermined rule as shifted from the center 161 to the arrows 162 and163 directions), and the shift amount of the remaining area thereof canbe a fixed value.

That is, interval between the adjacent photodiodes on the lightreceiving surface of the image pickup element 100 are changed linearly(or nonlinearly) toward the field angle ends from the center on thelight receiving surface.

Further, as shown in FIG. 1 and FIG. 2, the intervals between theadjacent photodiodes on the light receiving surface of the image pickupelement 100 are changed in accordance with positions on the lightreceiving surface of the image pickup element 100.

For example, the case where the image pickup element 100 is theback-surface irradiation type COMS sensor is assumed. In this case, onthe pixel transistor side, the photodiodes are formed in such a mannerthat intervals between the adjacent photodiodes on the light receivingsurface of the image pickup element 100 are equal. Further, on the lightincident side, the photodiodes are formed in such a manner thatintervals of the adjacent photodiodes on the light receiving surface ofthe image pickup element 100 are different depending on positions on thelight receiving surface. In this case, as shown in FIG. 1, thephotodiodes are formed along a light path of light that is incident fromthe opening portions. Further, the photodiodes are divided into piecesand silicon-epitaxially formed.

Further, as shown in FIG. 1, intervals between the inter-pixel lightshielding films 131 to 134 disposed between the adjacent photodiodes onthe light receiving surface of the image pickup element 100 are changeddepending on positions on the light receiving surface. Further, as shownin FIG. 1 and FIG. 2, the intervals between the lenses (OCLs 111 to 114and OCCFs 121 to 124) disposed on the image pickup element 100 arechanged depending on positions on the light receiving surface.

As described above, for the portions (OCLs, OCCFs, inter-pixel lightshielding films, and photodiodes) that constitute the image pickupelement 100, pupil correction can be performed. Here, the pupilcorrection is correction performed with respect to an exit pupildistance in accordance with a position of an image taking surface (see,for example, Japanese Patent Application Laid-open No. 2004-56260).

For example, in an optical system of the CMOS sensor, used is such anaspherical lens that, in a center portion of the image taking surface,the exit pupil distance appears to be short, and in a peripheral portionof the image taking surface, the exit pupil distance appears to be long.Further, in the case where the aspherical lens is used, toward theperipheral portion from the center portion on the image taking surface,the exit pupil distance is monotonously increased. In this way,depending on positions on the image taking surface, the exit pupildistance varies. For this reason, it is necessary to perform correction(pupil correction) for the exit pupil distance.

For example, the case is assumed in which the exit pupil distance on thecenter on the image taking surface is set as d1, the exit pupil distanceon an end portion on the image taking surface is set as d2, and the exitpupil distance is monotonously increased. In this case, it is possibleto perform pupil correction for an exit pupil distance d that satisfiesthe relationship of (d1+d2)/2<d<d2.

[Example of Manufacturing Process of Image Pickup Element]

FIG. 3 to FIG. 10 are diagrams each showing an example of amanufacturing process of the image pickup element 100 according to thefirst embodiment of the present technology. FIG. 3 to FIG. 10 showexamples in which a silicon epitaxial process and an ion injectionprocess are repeatedly performed, to increase the thickness of a siliconfilm of the photodiode. As a result, it is possible to increasesensitivity.

FIG. 3 to FIG. 7 show a first photodiode formation process. For example,as shown in FIG. 7, first photodiodes 189 to 191 and a trench shape 181are formed in a silicon wafer 180.

FIG. 3 shows a mark formation process. For example, a surface of thesilicon wafer 180 is oxidized to form an oxide film 175. Then, aphotolithography process is performed, and dry etching is performed,with the result that the trench shape 181 is formed in the silicon wafer180.

FIG. 4 shows a resist formation process. For example, by performing thephotolithography process, on the silicon wafer 180, resists 182 to 185are formed.

FIG. 5 shows an ion injection process. For example, by performing an ioninjection, in the silicon wafer 180, N-type regions 186 to 188 of thephotodiode are formed. Further, FIG. 5 shows a grayed region as a P-typeregion. It should be noted that the P-type region and the N-type regionare formed by performing the ion injection after patterning.

FIG. 6 shows a resist stripping process. For example, by performing theresist stripping process, the resists 182 to 185 formed on the siliconwafer 180 are stripped.

FIG. 7 shows an oxide film stripping process and an epitaxial (siliconepitaxial) process. For example, by performing the oxide film strippingprocess, from the silicon wafer 180, the oxide film 175 is stripped.Subsequently, the silicon epitaxial process is performed, therebyforming the first photodiodes 189 to 191.

FIG. 8 shows a silicon epitaxial process. For example, an epitaxiallayer 192 is formed. Further, in the trench of the trench shape 181, anepitaxial growth is caused with the trench shape maintained, with theresult that a trench shape 193 is generated.

FIG. 9 shows a pixel transistor formation process and a wiring process.For example, second photodiodes 194 to 196 are formed, and pixeltransistors 197 to 199 are formed. Further, wirings are formed.

FIG. 10 shows a back-surfacing process. It should be noted that, in FIG.3 to FIG. 10, for ease of explanation, an example of the photodiodeformation in the case where the pupil correction is not performed forthe photodiode is shown. In the case where the pupil correction isperformed for the photodiode, in the manufacturing processes shown inFIG. 3 to FIG. 10, the photodiode opening portions are shifted as shownin FIG. 1 and FIG. 2. That is, as shown in FIG. 1 and FIG. 2, byshifting the areas of the photodiode opening portions in accordance withthe shift amount described above, the pupil correction can be performedfor the photodiode. In this way, in the first embodiment of the presenttechnology, the image pickup element is manufactured in such a mannerthat the intervals between the adjacent photodiodes on the lightreceiving surface of the image pickup element are changed depending onthe positions on the light receiving surface of the image pickupelement. As a result, it is possible to suppress color mixing andshading.

Here, in the CMOS sensor (including infrared ray sensor), to obtain thesensitivity, it is necessary to increase the length (depth) of thephotodiodes (length in an optical axis direction). However, if thelength of the photodiode is increased, due to obliquely incident light,color mixing may occur. In view of this, in the first embodiment of thepresent technology, the silicon epitaxial process is used to layer thephotodiodes, thereby performing the pupil correction for the photodiode.

For example, as shown in FIG. 1, to the peripheral portion on the lightreceiving surface of the image pickup element 100, light beams L11 toL13 are incident thereon obliquely. In this case, it is also possible tosuppress color mixing due to the obliquely incident light beams L11 toL13, because the photodiodes are subjected to the pupil correction.Further, it is possible to increase the sensitivity of the image pickupelement 100.

In this way, according to the first embodiment of the presenttechnology, it is possible to perform the pupil correction for thephotodiodes. Further, because the pupil correction can be performed forthe photodiodes, it is possible to improve the degree of freedom ofcorrection amounts of the OCLs and the OCCFs.

Here, for example, an image pickup element having two-stage chipsexists. However, the image pickup element having the two-stage chipsinvolves a sensitivity loss in a wiring layer area thereof. Therefore, areduction in sensitivity loss is important.

Further, a front-surface irradiation type CMOS sensor exists in whichphotodiodes are obliquely shifted by repeatedly performing lithographyand ion injection. In the front-surface irradiation type CMOS sensor, apixel pitch, a pixel transistor, a pixel sharing method, and the likedetermine a photodiode opening position. Therefore, an asymmetricarrangement is caused, so the photodiodes are difficult to be disposedon optimal positions with respect to the OCLs and the OCCFs to besubjected to the pupil correction. Thus, there is a fear that furthercolor mixing may be caused.

In contrast, in the first embodiment of the present technology, for theOCLs, the OCCF, the inter-pixel light shielding films, metal wirings,and the like, the pupil correction is performed, and the pupilcorrection can also be performed for the photodiodes. As a result, it ispossible to suppress color mixing and shading.

Further, in the case where the photodiodes are formed by ion injection,due to energy rate controlling of an ion injection apparatus, it may beimpossible to form deep photodiodes. In contrast, in the firstembodiment of the present technology, the silicon epitaxial process andthe ion injection are repeatedly performed, the thickness of siliconfilms of the photodiodes can be increased. That is, deep photodiodes canbe formed. As a result, it is possible to increase the sensitivity withrespect to infrared rays and near infrared rays. Further, the pupilcorrection can be performed for the photodiodes (opening portions), andthus color mixing and shading can be suppressed.

As described above, for the inter-pixel light shielding films and thelenses (OCLs and OCCFs), the linear correction (or nonlinear correction)is performed, and also for the photodiodes, the linear correction (ornonlinear correction) is performed. Further, by performing the linearcorrection (or nonlinear correction) for the inter-pixel light shieldingfilms, the lenses (OCLs and OCCFs), and the photodiodes, it is possibleto achieve the image pickup element that has resistance to color mixingand shading. That is, it is possible to improve image quality of imagedata generated by the image pickup element. Further, it is possible toeliminate a limitation with respect to the film thickness.

2. Second Embodiment

In the first embodiment of the present technology, the example of theimage pickup element such as the back-surface irradiation type COMSsensor is described. In a second embodiment of the present technology,described is an example of the image pickup element such as afront-surface irradiation type CMOS sensor.

[Configuration Example of Image Pickup Element]

FIG. 11 is a cross-sectional view showing a configuration example of animage pickup element 200 according to the second embodiment of thepresent technology. FIG. 11 shows a configuration example of aperipheral portion (area on a peripheral side on light receivingsurface) of the image pickup element 200.

The image pickup element 200 is provided with OCLs 211 to 214, OCCFs 221to 224, metal wirings 231 to 238, pixel transistors 241 to 244, andphotodiodes 251 to 256. The image pickup element 200 is achieved by afront-surface irradiation type CMOS sensor, for example.

The OCLs 211 to 214, the OCCFs 221 to 224, the pixel transistors 241 to244, and the photodiodes 251 to 256 correspond to the portions havingthe same names shown in FIG. 1. Therefore, detailed description of thosewill be omitted.

[Example of Manufacturing Process of Image Pickup Element]

FIG. 12 and FIG. 13 are diagrams each showing an example of amanufacturing process of the image pickup element 200 according to thesecond embodiment of the present technology. It should be noted that themanufacturing process of the image pickup element 200 is common to themanufacturing process (first photodiode formation process) shown in FIG.3 to FIG. 8, so only a manufacturing process subsequent to the processshown in FIG. 3 to FIG. 8 will be described here.

FIG. 12 shows a surface oxidization process that is performed after thesilicon epitaxial process shown in FIG. 8. For example, the surface ofthe epitaxial layer 192 formed by the silicon epitaxial process isoxidized, thereby forming an oxide film 272. It should be noted thatfirst photodiodes 261 to 263 and a trench shape 271 correspond to thefirst photodiodes 189 to 191 and the trench shape 193 shown in FIG. 8,respectively.

FIG. 13 shows a photodiode formation process. For example, N-typeregions of photodiodes (first photodiodes 261 to 263) are formed, andP-type regions 273 to 275 of the photodiodes are formed, and resists 276to 278 are formed.

3. Third Embodiment

In the first and second embodiments of the present technology, theexamples of the two-stage silicon epitaxial image pickup elements areshown. In a third embodiment of the present technology, an example of amultistage silicon epitaxial image pickup element having three or morestages.

[Configuration Example of Image Pickup Element]

FIG. 14 is a cross-sectional view showing a configuration example of animage pickup element 300 in a third embodiment of the presenttechnology. FIG. 14 shows a configuration example of a peripheralportion (area on a peripheral side on light receiving surface) of theimage pickup element 300.

The image pickup element 300 is provided with OCLs 311 to 314, OCCFs 321to 324, inter-pixel light shielding films 331 to 334, photodiodes 341 to349, and pixel transistors 351 to 353. It should be noted that thosecorrespond to the portions having the same names shown in FIG. 1.Therefore, a detailed description of those will be omitted.

Further, a manufacturing process of the image pickup element 300 isdifferent in that the pattern of the photolithography process ischanged, and positions of photodiodes are shifted, but the remainingprocess is common to that shown in FIG. 3 to FIG. 10. Thus, a detaileddescription thereof will be omitted here.

[Configuration Example of Image Pickup Element]

FIG. 15 is a cross-sectional view showing a configuration example of animage pickup element 400 in the third embodiment of the presenttechnology. FIG. 15 shows a configuration example of a peripheralportion (area on a peripheral side on light receiving surface) of theimage pickup element 400.

The image pickup element 400 is provided with OCLs 411 to 414, OCCFs 421to 424, metal wirings 431 to 438, pixel transistors 441 to 444, andphotodiodes 451 to 459. It should be noted that those correspond to theportions having the same names shown in FIG. 11. Therefore, a detaileddescription of those will be omitted.

Further, the manufacturing process of the image pickup element 400 isdifferent in that the pattern of the photolithography process ischanged, and the positions of the photodiodes are shifted, but theremaining process is common to that shown in FIG. 3 to FIG. 8, FIG. 12,and FIG. 13. Therefore, a detailed description of those will be omitted.

It should be noted that in the embodiments of the present technology,the examples of the image pickup elements 100, 200, 300, and 400 areshown. For the image pickup apparatus provided with the image pickupelement 100, 200, 300, or 400, it is also possible to apply theembodiments of the present technology. Further, it is also possible toapply the embodiments of the present technology to an electronicapparatus such as a smartphone, a tablet terminal, and a personalcomputer, and an information processing apparatus.

It should be noted that the above embodiments are merely examples forembodying the present technology, and matters in the embodiments andmatters to define the invention in claims have correspondingrelationship. Similarly, the matters to define the invention in claimsand matters denoted by the same names in the embodiments of the presenttechnology have corresponding relationship. However, the presenttechnology is not limited to the embodiments and can be embodied byvariously modifying the embodiments without departing from the gist ofthe present technology.

It should be noted that the effects described in this description aremerely examples and are not limited. Further, other effects may beexerted.

It should be noted that, the present technology can take the followingconfigurations.

(1) An image pickup element, in which

-   an interval between adjacent light receiving elements on a light    receiving surface is changed depending on a position on the light    receiving surface.    (2) The image pickup element according to (1),-   the image pickup element being a back-surface irradiation type COMS    (Complementary Metal Oxide Semiconductor) sensor, in which-   the light receiving elements are formed in such a manner that the    adjacent light receiving elements are arranged at an equal interval    on a pixel transistor side, and the light receiving elements are    formed in such a manner that the adjacent light receiving elements    are arranged at different intervals depending on positions on the    light receiving surface on a light incident side.    (3) The image pickup element according to (1) or (2), in which-   the light receiving elements are formed along light paths of light    incident from opening portions of the light receiving elements.    (4) The image pickup element according to any one of (1) to (3), in    which-   the light receiving elements are divided into pieces and    silicon-epitaxially formed.    (5) The image pickup element according to any one of (1) to (4), in    which-   the intervals between the adjacent light receiving elements are    linearly or nonlinearly changed from a center of the light receiving    surface toward field angle ends. (6) The image pickup element    according to any one of (1) to (5), in which-   an interval between inter-pixel light shielding films disposed    between the adjacent light receiving elements is changed depending    on a position on the light receiving surface.    (7) The image pickup element according to any one of (1) to (6), in    which-   an interval between lenses disposed on the light receiving elements    is changed depending on a position on the light receiving surface.    (8) An image pickup apparatus, including:-   an image pickup element in which an interval between adjacent light    receiving elements on a light receiving surface is changed depending    on a position on the light receiving surface.    (9) A method of manufacturing an image pickup element, including:-   layering photodiodes by repeatedly performing a silicon epitaxial    process and an ion injection process; and-   changing an interval between the photodiodes adjacent on a light    receiving surface of an image pickup element in each layer depending    on a position on the light receiving surface.

REFERENCE SIGNS LIST

-   100, 200, 300, 400 image pickup element-   111 to 114, 211 to 214, 311 to 314, 411 to 414 OCL-   121 to 124, 221 to 224, 321 to 324, 421 to 424 OCCF-   131 to 134, 331 to 334 inter-pixel light shielding film-   141 to 146 photodiode-   151 to 153, 241 to 244, 351 to 353, 441 to 444 pixel transistor-   160 pixel area-   170 pixel-   171 photodiode opening portion-   231 to 238, 431 to 438 metal wiring

1. An image pickup element, wherein an interval between adjacent lightreceiving elements on a light receiving surface is changed depending ona position on the light receiving surface.
 2. The image pickup elementaccording to claim 1, the image pickup element being a back-surfaceirradiation type COMS (Complementary Metal Oxide Semiconductor) sensor,wherein the light receiving elements are formed in such a manner thatthe adjacent light receiving elements are arranged at an equal intervalon a pixel transistor side, and the light receiving elements are formedin such a manner that the adjacent light receiving elements are arrangedat different intervals depending on positions on the light receivingsurface on a light incident side.
 3. The image pickup element accordingto claim 1, wherein the light receiving elements are formed along lightpaths of light incident from opening portions of the light receivingelements.
 4. The image pickup element according to claim 1, wherein thelight receiving elements are divided into pieces and silicon-epitaxiallyformed.
 5. The image pickup element according to claim 1, wherein theintervals between the adjacent light receiving elements are linearly ornonlinearly changed from a center of the light receiving surface towardfield angle ends.
 6. The image pickup element according to claim 1,wherein an interval between inter-pixel light shielding films disposedbetween the adjacent light receiving elements is changed depending on aposition on the light receiving surface.
 7. The image pickup elementaccording to claim 1, wherein an interval between lenses disposed on thelight receiving elements is changed depending on a position on the lightreceiving surface.
 8. An image pickup apparatus, comprising: an imagepickup element in which an interval between adjacent light receivingelements on a light receiving surface is changed depending on a positionon the light receiving surface.
 9. A method of manufacturing an imagepickup element, comprising: layering photodiodes by repeatedlyperforming a silicon epitaxial process and an ion injection process; andchanging an interval between the photodiodes adjacent on a lightreceiving surface of an image pickup element in each layer depending ona position on the light receiving surface.